OAKLAND, Calif. — The weekly meetings of Mouthing Off!, a group for students at Mills College in Oakland, Calif., who identify as gay, lesbian, bisexual or transgender, always start the same way. Members take turns going around the room saying their names and the personal pronouns they want others to use when referring to them — she, he or something else. It’s an exercise that might seem superfluous given that Mills, a small and leafy liberal arts school historically referred to as the Vassar of the West, only admits women as undergraduates. Yet increasingly, the “shes” and “hers” that dominate...